GTSE1 promotes down-regulation of TP53 in a proteasome-dependent way. Nuclear export of TP53 facilitated by GTSE1 and MDM2likely makes ubiquitinated TP53 available to the proteasome machinery. GTSE1-mediated decrease of TP53 levels is needed for the G2 checkpoint recovery (cell cycle re-entry after DNA damage induced G2 arrest) and rescues cells from DNA damage induced apoptosis during S/G2 phase (Monte et al. 2003, Monte et al. 2004).